Carburetor



Amig. 8', 1944. v A' H. w. BYLAN 2,355,267

' CARBURETOR l I 4 Filed Seibt. 1-0, 1941 5 Sheets-Sheet 2 INVENTOR I.BM .wl WLM @2M/KM ATTORNEY Aug. 8, 1944. w. BOYLAN 2,355,267.

" CARBURETOR y Filed Sept. 10, 1941 5 Sheets-Sheet 4 IZZ FIG-1 1INVENTOR Patented Aug.- 8, 1944 atroit Lubricator Company, Detroit,`

I corporation of Michigan Application September 10, 19471', Serial No.410,251

(Cl. 261 il) 6 Claims.

` This invention relates tonew and useful improvements in carburetorsfor supplying a miX- ture of air and `fuel .to an internal combustionengine.

An object of the invention is to provide a carburetor which willsupplyaproper fuel mixture for all ranges of engine operation.

Another object isV to provide means for temporarily increasing the ratioof fuel to air for rapid acceleration.

Another object is to provide means for increasing the'ratio of fuel toair during high power demands. i.

Another object is to provide a carburetor which is particularly adaptedfor utilizing an anterior throttle valve.

The invention consists in the improved construction'and combination oiAparts to be more fully described hereinafter, the novelty of which willbe particularly pointed out and distinctly claimed. A I ,'y e

In the accompanyingl drawings to be taken as a part of thisspecification there rare fully and clearly illustrated several preferredembodiments of the invention, in which drawings:

Figure 1 is a top plan view of a duplex downdraft throttle anteriorcarburetor embodying the invention;

Fig. 2 is a view in sideelevation of the carburetor;

Fig. 3 is a view in section on the line 3 3 of Fig. 1;

Fig. 4jis a partial view in section on the line 4 4 of Fig. 3;

Fig. 5 is a'detail View in section on the line 5 5 ofFig.3;"

Fig; 6 is a detai'lview in section on the line 6 6 of Fig. 1; I

Fig. '7 is a detail view in section on the line 'I 'I of Fig. V4;

Fig, Sis a detail View in section on the ,line` 8 8 of Fig. 2;

Fig. 9 is an enlarged detail View Vof the metering valve in relation toits orifice in idling position;

Fig. 10 is a diagrammatic view of the duplex carburetor of Figs. 1` to9;

Fig. 10A is a diagrammatic view showing a position of the parts when thethrottle valve has .been moved vslightly toward open position.

Fig. 10B is a diagrammatic view showing the position of theparts whenthe throttle valve has been moved toa still further open position.

Fig. l1 is a view,y in side elevation of a single downdraft anteriorthrottle carburetor embodying,Y the invention, but having a portion ofthe fuel conduit in longitudinal section; I

Fig. 12 is a view in elevation looking from right to left of Fig. 11;

Fig. 13 is a view in longitudinal central section Fig. 14 is anenlargeddetailview in -section on the longitudinal center line of thefuel control or economizer means and taken on the line Ill-I4 of Fig.1l;

Fig. 15 is a detail view in lsection on the line I5 I5 of -Fig. 13 butshowing the nozzle an'd baille member in side elevation; y Fig. 16 is adetailtop plan view of the nozzle and bale member; v

Fig. 17 is a detail view of the blank from which the nozzle vand balememberis formed; and

Fig. 18 is a diagrammatic view of the single carburetor of Figs.`11-17.'

Referring to the drawings, Figs. 1-10 by chare acters of reference,numeral I designates generally the casing of a` duplex downdraft typecarburetor having a lower bodymember 2 on which through the mixingchamber vand taken on the vis mounteda cylindrical air inlet housing 3hav- Aing a bottom wall 4. The member 2 has a pair of parallelpassageways 5, 6 therethrough separated by a partition wall 1. Eachpassageway 5, 6 has a cylindrical air inlet and throttle bore 8registering with` an opening 9 in the housing bottom wall 4 for supplyof air from the common air inlet I0 of housing 3. Each passageway 5, 6is of general'Venturi form below itsbore 8 and has a throat I I with aconverging air inlet I2 and a diverging mixing chamber I3 having amixture outlet I4. .Extending transversely through the partition wall flandthe air inlet throttle bores 8, there isa throttle shaft I5. Mountedon the throttle shaft vin each .passageway there is a throttle valve-.I6ofthe balanced butterfly type, which valves are movable simultaneouslytoward o-pen position and toV closed position Secured to the outlet orunder side of each valve I6 and on the leading wing Il thereof there area plurality of air guide vanes I8 extending transversely to the throttleshaftand having their edges which `face the passageway wall curved as atI9, See Fig. '7, to provideA clearance on opening movement of the valve.The vanes I8 tend to eliminate swirling or turbulent flow of the airentering the converging air inlets I2. VExtending transversely throughthe wall l, there is a fuel discharge passageway 2li opening into eachof the passageways 5. t substantially at but on the mixing chamber sideof theirvthroats II, to provide horizontally directed oppositelydischarging fuel outlets or orifices ZI, 22 which are `alined with eachother and discharge substantially parallel to the aXisof the throttleshaft I5. I The wall of each passageway 5, 5 has ajrecess23, Fig. 4,opposing its orice 2l, 22. Extending between'each opposed orice andrecess and Abridging the passageway there are parallel air`ballleeplates 24 extending vertically at each side ofthe orifice sothatthe discharge from each orifice is longitudinally of 24 terminate inpositioning ears 26, 21 which extend respectively into the orices 2I,22- and `the recesses 23 to hold the plates against displacement. I I

In the air inlet I there is a disk `type choke valve 28 mountedeccentrically on a shaft 29 journaled in the side walls of the housing3. The valve 28 has an opening 38 therethrough controlled by a poppettype valve plate 3l which is urged to closed position by a coil spring32. The valve plate 3| is reciprocal on a rod 33 secured to the valve28, the rod'having a shoulder against which spring 32 abuts. The freeend 34 of rod 33 is engageable with the wall of housing 3 to limit themovement of valve 28 beyond full open position. v One end 35 of valveshaft 291 projects from the end of a sleeve 36, Fig. 1, extending fromthe housing 3. Rigidly secured on the external shaft end 35 there is alever arm 31. Within the sleeve 36 there is a coil tension spring 38havingone Vend engaging the lever arm 31 and its other .end anchored tothe sleeve 36 so that the spring 38 is operable to move the choke valve28 to closed position. Journaled on a stub shaft l 39 projecting fromthe external wall of housing 3 below the shaft there is a choke lever48, Fig. 2, having a bifurcated upper end providing spaced armsV 4I, 42engageable with the lever arm 31. The arm .42 in the position shown, isholding valve 28 in open position. `On clockwise movement of lever 40,the arm 4| is engageable with lever arm 31 to move the valve 28 towardclosed position against air pressure or to hold it tightly closed. Oneend of the throttle shaft I5 projects outlets I4 there is a cross slot48b connecting the mixing chambers I3 for synchronizing the pressurestherebetween.

The other end 49 of the throttle shaftV projects through a gear housing58 and has journaled on its external end'a hand throttle lever 5Iengageable with 'a shaft, Figs. 1, 4 and 6, pin 52 to move the throttlevalves I6 toward open position. Fixed on the throttle shaftY end 49within housing 58 there is a gear sector 53 which meshes with a gearsector 54 xed on a shaft 55journaled in a bushing (not shown) fixed incasing I by screw 56.

Supported by the casing member 2 and positioned at one side of thepassageways 5, 6 there is a constant level fuel reservoir having avliquid receiving chamber 51 with an inlet 58 for connection to asuitable source of fuel supply. The reservoir contains the usual inletvalve 58a` (Fig. l0) and iioat mechanism having a float 59 (Fig. 3)formaintaining a constant liquid level. An air inlet passageway 68 shownin dotted lines in Fig.

. 2 leads from the interior of air inlet housing 3,

' passageway 28.

by the wall 1 there is a tubular housing member 63, Fig. 3, having themid-portion of its bore providing a fuel passagewayll, Figsf 3 and 10,which is of substantially equal diameter to, and intersects themid-point of the horizontal discharge Below the reservoir liquid levelthe housing bore is of enlarged diameter as at 65, the enlarged boreintersecting the reservoir chamber 51 and extending therebelow toprovide a sump 66 which'is closed and sealed by a plug 61. Positionedconcentrically within the enlarged bore 65 there is la tubular member orhousing 68 having an annular ange and compression washer 69 fittingagainst the upper end of the enlarged bore. The upper end of the member68 extends into the passageway 64 and carries an annular metering valveorice member 18 having a fuel orifice 1I substantially at, but slightlybelow the plane of the reservoir liquid level. The orice member 18-abuts a downward facing shoulder to positively position the oriiicemember with respect to the reservoir liquid level. Within the member 68there isa longitudinal ow or well chamber 12 having' its upper endformed by the orifice member 18. Opening concentrically through thelower end wall of chamber 12 there is an inlet passageway 13 of reduceddiameter. The lower end of passageway 13 opens into a pocket or recess14 which forms a valve sleeve, the pocket 14 having its top edgechampfered and being of slightly less internal diameter than thediameter of passageway 13. Through the side wall of passageway 13 thereis a rectangular fuel inlet port 15 having its lower edge defining aportion of the top edge of pocket 14. 'I'he tubular member 68 is heldrigidly in position by a disk closure member 16 having labuttingengagement with a shoulder on member 68 and screw-threaded into the wallof bore 65 at its communication with reservoir chamber 51. The closuremember 1B thus provides in the upper end portion of bore 65 aroundmember 68 a fuelcontaining space, which is divided by an annularpartition plate 11 into an upper compartment providing a low speedaccelerating well chamber 18 and a lower compartment providing a highspeed accelerating well chamber 19. Through the wall of member 68 fromthe bottom end of chamber 19 into the passageway 13 there are aplurality of ports 88. The chamber 18is in communication with theinterior of member 68 by a port 8 I. In the casing member 2 directlyabove and separated from the chambers 18, 19 by an inclined wall 82there is' a chamber 83, Figs. 3, 5 and 10, having a vertical partition84 in the plane of the longitudinal axis of bore 65. The partition 84extends above thereservoir liquid level and divides the chamber 83 intoa low speed acceleratingfuel compartment 85 and a high speedaccelerating fuel compartment 86. The compartment 85 communicates withthe upper compartment 18 through an aperture 81 in wall 82 so that thecompartments 18 and 85 provide a low speed accelerating well. Thecompartment 86 communicateslthrough an aperture 88 in wall 82 with thelower compartment 19 to provide a high speed accelerating well. Thebottom wall 4 of the inlet housing 3 has a calibrated air bleed inlet 89therethrough opening into the top end of the chamber 83 so that the highand low speed acceleratingwells are open to atmosphere with controlledmaximum air, but subject to a reduced or sub-atmospheric pressure, and areduced air supply upon movement of choke valve 28 toward closedposition.

Extending through the orice 1I there is a passageway 13 and terminatesin thepocket 14;

I'hrough the walls of the tube 92 closelyadjacent Y, the valve member 90there is a cross passage93, which intersects the tube bore 94 to provideout#v let ports therefrom. The flow area of thecom-gg" way 91.

ber..|00. .The adjustment member. is adjustably screw-threaded throughaf sleeve member `|0| havinga longitudinally extending gear rack |02,the member |0| reciprocally fitting the guide- The upper end ofadjustment member |00 .has a longitudinal cross slot into which exicloses the 'upperA end of the guideway 91.

tendsa blade'adjustment member |03 which is journaled in and through acapmember |04 which A U- shaped spring strap |05 extends across the head'of'` member |03 and has its ends-frictionallylengaging thecircumference of capvmember |04 to bined outlets from the cross passage93 is sliglr'tl'f.

greater than the area of the calibrated bore "94-1,

Figs 3, 9 and 10. Thetube 92 has 7a cylindrical.'4 enlargement or plug95 intermediate its ends and which extends into, and in spaced relationto the vwalls of, passageway 13 so as to provide a cali;f brated annularinlet orifice to the chamber 12:'` The ow area of this annular oricedeterminesythe sub-atmospheric pressure in chamber 12 orL on theinletside of orifice 1I at whichair from' bleed 89 will sweep out the chamber18 andcham+ ber 12 above aperture 8|, discharging the fuel therefromthrough passageway into the mixf' ing chambers I3 of passageways 5 and0. For

a given size orifice around the plug 95 in the out:

let of passageway 13, the iiow area at the meterf` ing valve orifice 1|will regulate the sub-atmoslf` pheric pressure in the chamber 12, andaccorde ingly the size of the outlet orifice from passagef way 13 aroundplug 95 will determine the extentI 'of opening of the metering valve atwhich the low speed accelerating well will discharge The free end oftube 92 has a head 96 preferably o f the same diameter as the diameterof plug 95 and which fits the bore of pocket 14 to form therewith apiston or slide valve controlling admission of fuel from inlet port 15to the tube bore 94. The head 96 has its bottom edge champiered forguiding it into pocket 14 and it extends into pocket 14 at a distanceequal to or slightly greata er than the distance which plug 95 extendsinto passageway 13, this distance being less than the metering pintravel required to move ports 93 above or to the outlet side of orifice1|. The depth of pocket 14 is such that the valve 90 will be heldsubstantially .005 inch away from longitudinal seating in orifice 1|when head 99 seats against the bottom of pocket 14. The distance fromthe upper end of port 15 to the upper end or shoulder of head 96 issubstantially equal toor slightly less than the distance which plug 95extends into passageway 13 so that on movement of plug 95 out ofpassageway 13, the admission of fuel from port 15 to passageway 13 willbe controlled by head 96. The reduced external diameter of tube 92 belowplug 95 provides, upon movement of plug 95 out of passageway 19 enannular orifice into chamber 12 of sufficient size so that the highspeed accelerating well will discharge through ports 80 into chamber 12.

1 Above the fuel discharge passageway 2. the bore of` housing member 63,Fig. 3, is of slightly `enlarged diameter to provide a guideway 91. The

metering valve stem 9| extends upward into the .guideway 91 and has anend head or flange 98 which lits within a sheet metal coupling member 99which lits loosely in the guideway 91. Engaging the stem end 98 is theflanged end of an adjustment member |00 which extends through and holdthethreaded member :|00 in its adjusted position in sleeve member |0|thereby hol-ling the metering valveiniixed positionY relative to therack |02. Aileaf spring |05 engages the end of adjustment member |03 tohold it tightly against cap lmember |04 thereby sealing the aperturetherethrough and additionally opposing rotation of theadjustment membery|03. A helical coil spring |01- surrounds the valvestem 9|` and is `heldunder compression between a shoulder at the inner end .of `the guidewayand the base of a cup-like follower member |08 which reciprocallyfits-the guideway 91 and has its base or upper end wall engagingthecoupling., member 99 and acting'to move the metering valve out of orice1|. The rack |02 meshes with a pinion |09 fixed onthe end `of shaft 55so that the metering valve is mechanically `interconnected with thethrottle valves I6. The loose coupling formed by the coupling member 99between the adjustment member |00 and stem 9|- permits thetube 92 to`aline'with passageway13 and pocket 14.

When'. the carburetor is constructed to supply fuel mixture toa Ford-V8eng-ine, for example and solely for illustration of the relation ofcertain important dimensions tojeach other, the followingtable andmetering valve construction isset forth: i Inches diameter Passagewaythroats .870 Metering valve stemg9| '.171 Metering orifice 1| .156

Metering valve 90 is tapered at 21,41"` included angle to provide (Fig.9) a diameter at a of i156 substantially .154" from its minimumdiameter, and such that on the longitudinal valve center line:

Taper b ofA 2%" included angle, extends .030"

Taper c of 7 included angle, extends .030" Taper d of 16 included angle,extends .047 and Taper e of `40 included angle, extends .047"

yMetering valve diameter .150 at a is, at minimum idling speed position,substantially -.015 longitudinally out of or away from diameter .156" of@rinse 1|.

Pocket 14 .125." diam..080" long The operation of the carburetor ofFigs. 1 to 10 is as follows:` Whenit is desired to start the engine, thechoke lever '40 will be rotated inv a clockwise direction facing Fig. 2.to an extent depending upon engine temperatura'that is, in hot YWeather or when the engine has been running and it is desired to restartthe same there may be no movement required of lever 40.- However, incold Weather and with a cold engine the choke lever 48 will be rotatedso that arm 42 will permit spring 38 to move the choke valve to ortoward-closed position. This movement of lever 40 will act through link48 and lever 46 to rotate the throttle kicker cam 45 to automaticallymove the throttle valves I6 slightly toward open position. This movementof the throttle valves will act through gear sectors 53, 54 to rotatepinion |89 thereby movingV the metering valve 90 to a high idle speedposition. Asithe engine is now "turned-over sufficiently rapidly forlfiring, the sub-atmospheric pressure created in passageways 5, 6 willdraw fuel through the fuel inlet conduit, that is, from the floatchamber through port 15, inlet passageway 13, flow chamber 12 and pas;sages 64 and 28, to discharge from outlets 2|, 22 into the passagewaymixing chambers V|'3. If the speed of the engine cranking is sufficientthere Will also be a suliicient differentialof reverse air pressure onthe fuel wells from the fuel reservoir so that fuel will be dischargedupwardly from the wells through air bleed inlet or orifice 89 into theair inlet I anterior to the throttle valves I6. This supplementalstarting fuel from the wells will mix with minimum-air passing the chokevalve 28 and be supplied therewith'to the mixing chambers I3. As soon asthe engine res and is running under its own power the increasedsub-atmospheric pressure or pressure reduction in passageways 5, 6 willmove the choke valve 28 toward open position against the force of spring-38 thereby automatically supplying sufficient air for cold engineidling operation. Opening movement of choke valve 28 will increase theair pressure on air bleed orice 89 so' that fuel will no longer feedtherethrough into the air inlet I0. However, the choke valve 28 from analmost closed position to about from full open position will reduce theair flowto and vthe air pres- 'sure on the wells through orifice 89. Asa result, the quantity of fuel supplied to passageway 28 will beincreased, thereby assuring the supply through the cold manifold to theengine of a proper air-fuel mixture for full range engine operation. Therichness of the fuel mixture of course decreasing as the choke valvemoves or is moved toward open position as a result of air Vflow into thefuel conduit through orifice 89. In

v:extremely cold Weather starting when choke lever arm 4| engages thearm 31 to lock choke valve 28 in closed position, the idling speedoperation of the ,engine will open -poppet valve 3| yto supplysufficient air for continued idling speed operation. When the engine haswarmed up, the choke lever 40 Will be returned to the position shown inFig. 2 and the a'rm42 will be holding the choke valve in full openposition as in Fig.3.

If the throttle valves |6are moved from idlin speed position toward openposition to increase 'the air flow through the passageways 5, 5to the-sponding to say 10 milesper' hour level road car speed,lFig. 10A, themetering valve 90'Wil1have moved sufiiciently Vout-of its orifice' 1| sothat the sub-'atmosphericpressurein the flow cham@ its cross passage 93.

ber 12 will cause the well chamber 18 and the flow chamber 12above'aperture 8| to empty into the fuel conduit, the supplemental fuelfrom the Well being followed by air from the bleed orifice 89 which ismetered at the calibrated aperture 8| so that uponemptying of the lowspeed accelerating well an emulsion of fuel and air will be fed throughthe chamber 12 to the metering valve orifice 1|. are opened stillfurther, Fig. 10B, and sufficiently to draw the plug out of inletpassageway 13 which will occur at about 45 miles per hour level road carspeed, the well comprising chambers 19 and 86 will discharge its fuelthrough ports 88 into the fuel conduit and this supplemental fuel willbe followed by air from bleed orifice 89 which is metered by calibratedports 88. Simultaneous with the discharge of Well chamber 19, the tubehead or valve 96 will have moved out of pocket 14 thereby opening theeconomizer tube bore 94 directly to inlet port 15 from the fuelreservoir so that supplemental fuel will be continuously dischargedfrom-cross passageway 93 directly into the fuel conduit.

The 'accelerating wells serve to provide the `necessary over richmixture for quick acceleration either from idling or from part openthrottle position. When the throttle valves I6 are quickly opened butnot suii'cient to draw the plug 95 out of inlet passageway 13, thesub-atmospheric pressure in flow chamber 12 acting on the low speedaccelerating well decreases and Well chamber 18 will discharge thenecessary quantity of solid liquid fuel into the fuel conduit to assurethe discharge of the necessary enriched mixture from outlet I4.Continued operation of the engine at part open throttle will not emptythe well chamber 19 of the high speed accelerating well, but if thethrottle valves are quickly opened from part throttle sufiiciently towithdraw the plug 95 from inlet passageway 13 then there will be asubstantially instantaneous discharge of solid liquid fuel into the fuelconduit from the high speed accelerating well chambers 19 and 86 toprovide the necessary enriched mixture to the engine for high speedacceleration. As noted above, the economizer passage 94 will be openedwhen the well chamber 19 discharges and therefore supplemental fuel willcontinue to be discharged through passage 94 at this throttle valveposition and for all further open positions of the throttle valves.Should the throttle valves be .quickly opened for rapid accelerationfrom idling vposition to an open throttle position corresponding to alevel road car speed of 45 miles per hour or more, then there will be asubstantially instantaneo-us discharge of solid liquid fuel from both ofthe accelerating wells into the fuel conduit and this supplementaldischarge which suddenly increases the ratio of fuel to air will besupplemented instantaneously by the continuous discharge through tubebore or passage 94 and 'Ihe chamber 86, however, will not completelyempty until the engine has attained a speed corresponding to a car speedof about 8 or 9 miles .per hour. It will be noted that upon movement ofplug 96 to open the economizer bore 94, the mixing chambers I3 will besupplied from two fuel supply means or jets, each feeding into the fueldischarge cross passage 20, one of these jets being the bore ofeconomizer tube 94 and the other being the annular passage- Way throughtubular member 68 around the tube 92.

In Figs. 11-18 inclusive, there is shown a single When the throttlevalves I6v garage# t'ype carburetor which operates v'substantially-irithe manner above described for the duplex carburetor but which `hascertain structuralfch'anges and additional features. Thissinglecarburetor has a one-piece body l| I having amain vertical passageway II I therethrough witha top air -inlet I I2 and a bottom mixture outlet I|3. rIlhe upper portion of body ||0 forms a cylindrical-air'inlethousing ||4 which contains an eccentric disc type choke valve or platel|5 mounted on a shaft I I6 journaled in the housing side walls. Throughthe valve ||5 there is an air opening I |1` controlled lby a4spring-pressed plate `type poppet valve I I8 such asis shown `in Fig.3.4 One end of shaft ||6 extends throughthe housingwallland has a lever||9 rigidly fixed thereon. Pivotedon a bracket-carried studverticallyliabove shaft I |6 there is Aa choke'lever |2I'which extends`below the shaft 6 and has atension coil spring |22 connecting it toa-transverse arm |23 on lever |.|9.` The arm |23 extends rfreely througha slot or aperture .|24 in lever |2|` and isheld against one end |25'ofthe slot by! the spring `|22 so that valve ||5 is heldin wide openvertical position. A pull and pushrod `may belconn'ected to theleverpost |26 to move theA lever |2I. As the lever |2| is rotated clockwiseortoward the left, facing Fig. 11, the spring |22 willpull thefchoke valveto closed position. When the choke valve has been. closed, the continuedmovement of le ver |2| will move slot end |25 away from arm |23 andincreasingly load the valve 5. The other slot end |21 is engageable-witharm |23 to positively hold the valve ||5` in closed lposition or tolimitits openingV movement' by air pressure.

Below the housing ||4, there is a cylindrical air inlet and throttlebore|28 within which there is an anterior balanced buttery-type throttlevalve |29 mounted on a throttle shaft/|30 `extending transverse to shaftI |6 and journaled-i-n thewalls of `body H0. 1 Oneend of shaft`|30projects externally'and has rigidlylxed thereona throttle lever |3|. Theother `endof shaft |30 extends intov a hollowliboss |32,.se`e2Fig. -l4;and

has a piniongear |33 fixed thereon; 'The throttle lever `|3| has. anidle Vadjustmentscrew` |34 jcooperable with alever carried kicker cam`|35 journaled on a stud |36. .The cam lever is A'connected `by al thrustandpull link or rod |31lto an arm of choke' shaftleverrl I9; Therefore,as choke lever |2| ismoved clockwisafthe rod|31 is moved downward soasto rotate cam |35 coun terclockwiseinto engagement with screw |34 toopen the `throttle for coldengine `high speed idling.` r

In the .passageway III, Fig`s`.13, 15and 18, "below the throttle valve|29, there isla/tube |38 o'f Venturi form having "a throat vv|39;"Opening throughthe body |=|0 Sandi tuber|38,wthere isa horizontal, fueldischarge" |40=Jfsubstantially `at the throat |39 and fparallelrto`thrttle'shaft |30; Bridging the inlet end ofthe tube .|38 and thethrottle bore |28` there-is anozzle and .bafe mem# ber- |4| having4 a.pair of parallel baiiieuplates |42; |43 extending parallelto `anddirectly below the throttle shaft |30 and embracingv the. dischargeopening |40. The .plate |42\is.cutto.trthe inlet end of passageway andseat on theconverging end of tube |38. .The .plate `|ll2fextends upwardsubstantially to the shaft |30so as toblockair ow .diagonallyA acrosslthevpassageway below the leadingV `edge of..valve |291sandi-=diagonally'across the outlet of l passageway.' .I 405;. Theimem.- ber |4|1isofgenerally U-fshapeclwform having its base. yportion .|441cut to conform.with .the .outlet of :passageway 1| 40 7"and vthaving? a lip?` 1| 45:extending downward f and outward from passageway' |40.Extending-betweerplates `|'42-,1 |43 there is.- acap portionf |46 whichis: bent outward' and-.downward to forn `theroof ortop Walllof thenozzle. Atoneside:of.the body. |0 there .is a constant level-.fuelreservoir'. |41, Fig.. l1, Ahaving an Lair inlet passageway 41@ openinglupward through the-.fbody' ||0 'into thefairinlet ||2 4above valve ||5'so that-theiloat chamber is open to' atmosphere above` the liquid 1.level.` f .The chamber. .I 41 has affuel inlet |48.and. therusualoatoperated inlet valve` |48`a (Fig. 18.).. Between-the reservoir and the`passageway1||.|,.:the. wall of body 0 has aninclinedabore"therethroughl'with a fuel passageway |49, Figsl` 14.1`and18,. which'intersectsthe horizontalrfuel passageway |40.l Belowpassageway|49,lthe boreis enlarged. as at |50., to` receive a tubular.memberor housing I 5| .which -ts` the bore |50.; Fttingvinthe lupper end:of member il 5| and lin the; lower end. ofy passageway |49, there is ametering orice member.v |52 "having" a metering lvalve orioe or port53.5. The `tubular member \|.5'| and orice 'member |52- are heldinposition against `the I downward *facing-1 end wall ori shoulderof `bore|50 :byla'screw plug l| 54 which closes the lowerend'of the. bore. Theorifice |53 is v.positioned substantially at; butv slightly below the.plane of the reservoirfuel` llevel. designated Theforice .member |52forms the upper end of `a fuel flow andV wellwchamber '|55 `into the`lower end of which a concentricv 'fu'el '2 inlet passageway |56 opens.Atfits -bottomendi the passageway .I 561terr`ninat'eslin a cylindricalpocket or recess |51'. having. itsbore diameter `reduced slightly:.relativet'o the bore of passagewayv |56. A "fuel-ductorr passage |58`leads from the reser voir |41 into the bore |50.and opens intopassage;way ;|56 slightlyiabovepocket |51th'rough .an aperture |59. (Fig. '11).`lAtthe side of the-` bore |50^,.the body .l0-has a cylindricalfuel-chamber |60 which is divided internally' byF-a cylindricalpartitionorftubulanmember |6I into am annular surrounding-fuelwelllchamber-IISZ for lowI 'speed acceleration, and f into a-centralfuel Swell chamv .ber |6134 `for highlspeedacceleratiorij.'fI'hef-parti'` tion 1|.6| :is held in` lo'ositionbya` plug :|64 whichcloses. andseals the. top .of chamber |60. The plug |64hasatubularextensio`n|65fwhich re'- ceilves i and lpositions 'theuppe'r end 4ofpartition |61` and hasa;..fsurrounding flange |66 fitting theboreoffchamber f 60:1 The annular air cham`` loer` or:mani'fold".|61between flange |66"and\1the head of .plugl 64=is Ain vcommunicationwith`chamber |63 -byair inlet'ports'|68 in extension |65 and is`ingcommunioation with` chamber |62 by air inlet.Y ports |69 in, flange166.. `Air i'sv suppliedi'to 'air chamber. |611 .by'a duct `or conduit|10.` which extends'upwardthroughthe wall of .body |.I0 and hasia.calibrated,inlet1|;1| .(vlig; 11) openingfinto 4the ain-inletgllZlbetweenichokenvalved I5 and throttle valve |29. From the bottom endoffac.- celerating4 chamber; |62, a. -ductz-` |12 l leads into bore|50-and opens through a calibrated port or orifice |'|3` into` the wellchamber 5.5.` 1 From the bottomlehnd ofaccelerating. chamber .|63 a ductor C QnduitJ 14 leads into borezl Eiland opens into an annular .orl.circumferential groove. |15 from the'.l:ottom end of -valve |8| "andextending lconcentrically. therefrom, there is an economlizer tubeV or,tubularmember |82" vwhich extends through passageway |56 and intopocket |51; The `tube |82 has Vacalibrated bore |83 forming a high speedfuel; ductwhichopens ,through a calibrated outletfcross passage |84substantially at, valve .|8| andl into chamber, |55, Intermediate itsends, the tube |82 has a circumferential enlargement |85 providing aplug with'a downf,

wardfacing shoulder which-'extends into passageway |56 to provide acalibrated annular. fuel inlet orifice into chamber |55. The end of tube|82 has a head |86 which ltsthe bore of Vpocket |51 to provide a; slidevalve controlling admission of supplemental fuel to high speed duct |83.These parts are-,arranged and constructed as above described for theduplex carburetorj so that as plug |85 pulls out of passageway |56, thehead or `valve |86 pulls out of pocketl |51 and limits flow topassageway |56 from floatchamber'duct |58. x y

, The metering stem |80, Figs. 14 and 18, abuts the end of ascrew-threaded adjustment-member |81 to which it .is vconnected, forrelative rotation by a coupling member |80. A spring |89 surrounds thestem |80 and acts upward against the coupling member |88 `to vurge themetering valve |8I upward out of its orice or 'toward open position. Theadjustment member |81 is adjustabl-y'threaded in a rack member v|88which reciprocally ts 'its bore and has gear teetli |90 meshing withpinion |33. The metering valve |8|V is adjustable Lrelative to its oriceto deter.:

mine the idling jfuel flow by a key member |9| which fits slidably in aslot |92 in the end of adjustment member |81. i rotatably fits in anannular plug |93 which closes the upper end of the metering pin bore. Aspring clip |94 :holds the key member |9| against unintended rotationwhich wouldchange the setting of the metering valve. .f n E A .Theoperation'of this single carburetor will be clear from the foregoingdescription and the description ofV operation ofv theiduplex" carburetorof Figs.; 1-10. The annular orifice areav provided in passageway |56 byplug |85 determines the open position of metering valve |8| and theAsub-atmospheric pressure on the'finlet side of orice |53 in chamber |55at which the low speed accelerating well, comprising annular chamber |62and the portion'of chamber |55 above orice |13, will dump its'fuelintoLthe fuel conduit.` AThe extent VOfopeningl or the open position ofthe metering valve |8| at'which 4plug' ervoir fuel leveland Vat a pointbetween the point of discharge of said first-named well and saidmetering valve, means determining the open positionof said lmeteringvalve at which said second well will supply air to saidV conduit, meansdetermining the openposition of said metering valve fat which saidfirst-named Well will supply air to `said conduit, and means operable tosupply fuel to said conduit adjacent said metering valve upon supply ofair to said conduit from said firstnamed well.

2.A carburetor comprising a casing having a passageway therethrough withan air inlet and 'a-mixture outlet, a constant level fuel reservoir,

afuel conduit leading from said reservoir and discharging into saidpassageway, a metering valve controlling .fuel now through said conduit,an atmospheric fuel well for supplying fuel and air to said conduit onthe inlet side of said metering valve and below the reservoir fuellevel, a second atmospheric fuel well for successively supplying fueland air to said conduit below the reservoir fuel level and at a pointbetween the point of discharge of said first-named Well and saidmetering valve, means determining the open position of said meteringvalve at which said second well will supply air to said conduit, meansoperable by said metering valve and determining the open position ofsaid metering valve at which said first-named well will supply air tosaid conduit, and means controlled by said metering valve and operableto supply fuel to said conduit adjacent said metering valve upon supplyof air to i said conduit from said first-named well.

The key member |9| i 3. A carburetor comprising a casing having apassageway therethrough with an air inlet and a mixture outlet, aconstant level fuel reservoir, a throttle valve, a main fuel conduithaving a said passageway, a metering valve operable by Y Y said throttlevalve and controlling ow through |85 moves out of its orifice orpassageway|56 determines the dumping of the high speed ac-'11`celerating well formed =by.central. chamber. |6325@- a fuelconduit.leadingfronr'saidreservoirf'and discharging intosaidpassag'eway, a metering valve controlling VVfuel flow through saidconduit, 1an atmospheric fuel well for supplying fuel `and air to. saidconduit' on the inlet side of said'meter- :ing valve and below thereservoir fuel-level, a 'secondatmospheric fuel` WellI for successivelysupplying fuel and airito said conduit below-the 'res- 15 saidport, lowspeed accelerating means to supply a quantity of fuel followed by air tosaid conduit at an open position of said metering valve, high speedaccelerating means to supply a quantity of fuel followed by air to saidconduit ,at a further open position of said metering valve, and meansmovable with said metering valve and operable to supply fa meteredquantity of supplemental fuel to said conduit for all open positions ofsaid metering valve vbeyond a predetermined open position, said movablemeans being initially positioned to discharge fuel into said conduitlanterior toV said metering rport and on movement of said metering valvebeing positioned to .discharge into said conduit posterior to saidmetering port.

,4,;A.carburetor Vcomprising a casing having a mix-ing chamber with anair inlet and a mix-1 tureoutlet, a throttle valve for said mixingchamber, a constantl level fuel reservoir, a fuel conduit leading fromsaid reservoir to said mixing chamber; and1having a flow chamber with.an outlet vo riiice;andY anV inlet passage, a metering valve cooperablewith said orifice, a tube having an openend and extending from saidvalve through said, flow Chamberland said passage, a pocketopeningintosaid passage and receiving the end lof said' tube, -a head onsaid tube slidably fitting saidpocket, a circumferential plug on saidtube and posltionedwithinsald passage to restrict ow tol said wichamber,opening movement of said meteringV .valveacting to move said plug out ofsaid-"passage: and vsimultaneously `to .move said head. out'of .saidpocket and intcposition to restrict ow through said passage, said tubehaving an outlet adjacent said valve and positioned on the outlet sideof said orifice upon movement of said head out of said pocket so thatsaid tube will discharge fuel into said conduit beyond said valve, anair bled fuel well discharging into said ilow chamber, said plugcooperating with the wall of said inlet passage to determine the openposition of said metering valve at which said well will discharge, anair bled fuel well discharging into said inlet passage, said plug onmovement out of said inlet passage establishing ow from saidsecond-named well, and means operatively connecting said metering valveto said throttle valve.

5. An anterior throttle carburetor comprising a casing having a mixingchamber with an air inlet and a mixture outlet, an anterior throttlevalve for said mixing chamber, a constant level fuel reservoir, a fuelpassage having an enlarged bore at its lower end communicating with saidreservoir, a tubular member in said bore and having an internalelongated chamber and an external shoulder seating against the end wallof said bore, said tubular member having at its upper end a meteringorifice substantially in the plane of the reservoir fuel level, saidfuel passage having a transverse passage portion leading from above saidorifice and having a fuel outlet opening into said mixing chamber on theoutlet side of said throttle valve, a guideway alined with said tubularmember and extending from said fuel passage, a metering valve extendinginto said orifice and having a stem extending into said guideway, asleeve member reciprocally tting said guideway and having an externalrack, gear means interconnecting said rack and said throttle valve, saidsleeve member being adjustably screw-threaded on said stem to determinethe position of said metering valve relative to said throttle valve,said tubular member having a pocket at its lower end and an inletpassage extending from said pocket to said elongated chamber, a tube onsaid metering valve and extending into said pocket, a head on said tubeand fitting said pocket to cut off fuel admission to said tube, acircumferential enlargement on said tube within said inlet passage andrestricting iiow to said elongated chamber, said tube having an apertureclosely adjacent said metering valve for discharge of fuel from saidtube, an air bled well discharging into said elongated chamber, an airbled well discharging into said inlet passage, said tube aperture, saidhead and said enlargement being so related to said metering valve thatin the full open position of said metering valve, said enlargement willbe out of said inlet passage, said head will be out of said pocket andsaid tube aperture will be positioned on the outlet side of saidorifice, means on said throttle valve to guide air flow to said mixingchamber, and baflie means in said mixing chamber deilecting air ilowaway from said fuel outlet.

6. An anterior throttle carburetor comprising a casing having apassageway therethrough having an air inlet and a mixture outlet and aconverging-diverging portion forming a throat, a butterfly throttlevalve in said air inlet and controlling the volume of mixture dischargedthrough said outlet, said casing having a fuel outlet orice adjacent andon the outlet side of said throat and discharging parallel to the axisof said valve, a vane on said throttle valve and in a plane transverseto the plane of discharge from said orifice, said vane being positionedon the mixture outlet and leading side of said throttle valve, a baffleplate positioned at each side of said orifice and extending across saidpassageway parallel to the plane of discharge from said orifice, a angebridging the space between said plates and shielding the air inlet sideof said orice, means on said plates extending into said orifice tolocate said plates, and means to supply fuel to said orifice.

HENRY W. BOYLAN.

